Answer:

Step-by-step explanation:
Let p be the potato chips
Let s be the two-liter sodas
Then, if Great Foods Grocery Store is selling 2 bags of potato chips for $6.50 and 5 two-liter sodas for $3.00:

For Best Foods Grocery Store:
2 bags of potato chips for $5.00 and 3 two-liter sodas for $2.00.
Answer:
15
15
10
Step-by-step explanation:
3/8 x £40 = £15 for Sarah
3/8 x £40 = £15 for Fiona
2/8 x£40 = £10 for david